And eli t



(Model.)

"W. A. JOHNSTON,

A, W. BROWNB, E. Vfr.Y STARR, AA,

W. GILBERT.

J. DENTAL ENGINE HAN D PIECE.

No. 287,683. Patented 00A. 30, 188s.

VIV/V".

N. PETERS. Phum-Lhngmphnr. Washngian. D. C.

` 'UNITED t STATES PATENT OFFICE. e

WILLIAM A. JOHNSTON, OF OLIFTON, AND ARTHUR W. RROWNE, OF WEST- FIELD,NEW YORR, AND ELI T. STARR AND JOHN W. GILBERT, OF PHILA- YDELPHIA,PENNSYLVANIA, -AssIeNORs TO THE S. S. WHITE DENTAL MANUFACTURINGCOMPANY, OF PHILADELPHIA, PENNSYLVANIA.

DENTAL-ENGINE HAND-PIECE.

SPECIFICATION forming part of Letters Patent No. 287,683, dated OctoberVSO, 1583. Application filed February 12, 1883. (Model.)

0 all whom t may concern: Be it known that we, WILLIAM A. JOHN- STON, ofthe village of Clifton, county of Richmond, and State of New York,ARTHUR W. Y BROWNR, of the village of Westfield, in said county andState, and EDIT. STARR and JOHN NV. GILBERT, both of the city and countyof Philadelphia, in the State of Pennsylvania, have r4jointly inventedcertain new and useful Improvements in Hand-Pieces or Tool-Carriers,more especially adapted for use with dental and surgical engines andelectromotors, of whichthe following is a speciiication.

Our invention relates more especially to the hand-pieces ortool-carriers of the powerdriven engines used by dentists and surgeonsin their operations 5 and it constitutes moreparticularly an improvementupon the hand-piecesV shown in the patents of Johnston and Browne,

' V20 No. 213,662, of March 25, 1879, and in the patents of E. T. Starr,Nos. 233,707, 233,708, and 233,709, of October 26, 1880.

` The prime objects of our invention are,

first, to provide an absolutely secure and true tool-fastening, wherebythe tool shall at all times be firinly seated in the socket of itsrotary spindle without liability to either lateral or end playtherein;second, to providefor readily exposing the working parts of thehand-piece for oiling, cleaning, or inspection Without disturbing theadjustment of the bearings of the` rotary spindle of the hand-piece,third, to permitthe bit to be changed while the engine v is in motion,and enable the rotary spindle to f run as freely with the tool-fasteningreleased as when a tool is clamped inthe socket of the rotary spindle;fourth, to facilitate the substitution of one bit or tool for anotherwithout changing the position of the hand-piece in the 4o hand 5 fifth,to provide a nose-cap covering the end of the spindle, the ready removalof which facilitates the oiling and cleaning of the front end ofthespindle; sixth, to retain the feature of drawing the shank of the toolfirmly into place in the spindle-socket when inserted therein, as shownin the Johnston and Browne patent above mentionedhwhile providingagainst the accidental removal of the'bit or tool when a pull cut isbeing made; seventh, to preventthe liability of the lubricating-oil usedabout the hand-piece from soiling the fingers of the operator or theface of the patient; eighth, to prevent the several screws used in theconstruction of the hand-piece from being lost or mislaid in takingapart the hand-piece; ninth, to so construct the various parts that anyof them can be renewedwithout sacrificing the other parts of theorganization; tenth, to improve the arrangement of the journals andbearings of thehand-piece; eleventh, to provide an improvedconnectionbetween the rotary power-driven shaft ,of the engine andtherear or butt end of the rotary spindle; and,

twelfth, to improve the construction of the front or socket end of thespindle, so that its tapered j ournal may be readily removed, when worn,and replaced without sacrificing the rest of the spindle.

The subject-matter claimed herein as of our invention is particularlypointed out at the close of the specification.

In the accompanying drawings we have shown all our improvements asembodied in the best way now known to us.

It is to be understood that some of these improvements maybe usedwithout the others, andk in hand-pieces diering in their details ofconstructionfrom that particularly shown.

In said drawings, Figure 1 is a longitudinal section through ahand-piece embodying our improvements; and Fig. 2,A a similar view.through a portion thereof, the tool-locking mechanism of the hand-pieceand its operating devices being shown in a position different from thatshown in Fig. 1. Figs. 3, 4, and 5 Y are transverse sectional views onthe lines x x,

Fig. 6 is a-perspecy y, and z z, respectively. tive view of the rear ordriving end of an operating-tool adapted to the socket of the rotaryspindle of the hand-piece, aud Fig. 7 is a view of the split or squeezenut which locks the pull-collar of the spindle in place.

The hand-piece casing in the example shown consists of a handle-section,a, a second secof the casing, said shank-section being connected withthe section a by means of a swiveljoint, as in the well-known hand-pieceof the S. S. White dental engine, whereby the handle-section may turnfreely to conform to the movements of the hand of the operatorrelatively to the shank-section. Said shank-section is permanentlyconnected with the outer or free end of the iiexible sheath of theengine which envelopes the flexible driving-shaft, as usual. Neithersaid sheath nor said shaft is shown in the drawings, as to depict themtherein would be unnecessary. The outer or free end of the flexibledriving-shaft is connected to the rear or butt end of the rotary spindleB of the hand-piece in this .organization by means of asocket-connection, b. This socket piece or connection is connected atits rear end, preferably by soldering, as usual, with the front end ofthe flexible shaft, so as to form a permanent connection therewith. Thefront end of the connection b is'also socketed, and the socket isprovided with a female thread at its inner termination, so as to permitthe connection to be firmly screwed upon the malethreaded end of thespindle B, so as to form a firm but detachable connection therewith.rlhe spindle B has a tapering shoulder, b', formed thereon,corresponding with the tapering or conical mouth of the socket of theconnection b, whereby upon firmly screwing up said connection a 'firmdriving-connection is formed, even as against back rotation of theengine. The enlarged frictional surfaces afforded by the cone shoulderand the conesocket very materially aid in making the connection a securedriving one, in whichever direction the driving-sh aft may turn. Thespindle B has its bearings in the hand-piece casin g. The front end ofthe spindle is socketed for the reception of the tool-shanks, as usual,and has a taper or cone journal which fits a corresponding bearingformed by the front end of the handle-section of the casing. Theadvantages of a cone-journal for the rotary spindle at the front or noseend of a hand-piece arer well established, and need not be reiteratedhere by us.

The handle-section a of the casing is usually made of brass. In order toafford a durable bearing for the tapered end of the spindle, wepreferably construct the bearing therefor at the nose of the hand-pieceof a hardened-steel thimble, a3, soldered or otherwise suitablyconnected to the front end of the handle-section proper. By this means,when the said thimble is worn too much for the successful operation ofthe hand-piece, it may readily be removed and a new one substituted forit. ln order, likewise, to provide for the renewal of the cone-journalof the spindle when worn, so as not to sacrifice the entire spindle, weconstruct the cone of the spindle of an externally-tapering tube, b2, ofhardened steel, so connected to the reduced end of the spindle as to beremoved by a machinist when worn and a new one placed thereon. rlhepreferred construction is to reduce the front end of the spindle B, asclearly shown in Fig. 1. The hardened cone-journal b2 is then `forced onthe reduced socketed end of the spindle and firmly soldered in place. Itis then centered by the socket in the end of the spindle, and the coneground to shape and trued exactly with the center of the socket. Thesocket in the front end of the spindle B for the reception ofthetool-shank has atapered mouth, as in the Johnston and Browne patentbefore mentioned, for the reception of the cone-shoulder formed on theshank of the operating-tool. It will be noticed that the end of thespindle B projects a little beyond the end of the hard-metalthimble-piece a, before described. This projecture of the front end ofthe spindle beyond the casing proper is more especially for the purposeof exposing the end of the spindle for the purpose of cleaning andlubricating the front journal thereof. If this spindle, however, was notinclosed, saliva, grit from the teeth, and other impurities would findready access to the front bearing of the hand-piece, while thelubricatingoil would also escape and soil the fingers of the operatorand face of the patient. To avoid these objections we provide the frontor nose of the hand-piece with a tapered cap, (3,' internally threadedat its inner end, so as to fit the threads a4, formed on the exteriorhardmetal thimble-piece, a. The cap C, when screwed in place, as shownin Fig. l, fully covers the protruding end of the spindle and overlapsthe cone-shoulder formed on the toolshank, whereby there is formed, asclearly shown in. said figure, a space, a5, which most effectuallyprevents the entrance of saliva and other deleterious matter to thefront. bearing of the hand-piece, while the exudation or escape of thelubricant is also prevented. This screw-cap C is readily screwed on ortaken off from the front end of the hand-piece as occasion requires.

The rear axial bearing of the spindle B is provided in the union-pieceor collet D. The spindle B is prevented from inward endwise movement inthe hand-piece casing by means of a thrust-bearing formed by a collar,E, fitted upon the spindle, and held thereon by means of a set-screw, c.This thrust-collar is readily removable from the spindle by looseningthe set-screw c. When in place upon the spindle, however, its positionis determined by means of the shoulder b, formed on the spindle, thecollar being forced up against said shoulder. The set-screw c, which hasa tapered end fitting a longitudinal groove, b, of the spindle, is thentightened up, causing its pointed or cone end to bear against auinclined shoulder formed by a slot, c, in the spindle, whereby thecollar E will be forced firmly up against its shoulder l3 on thespindle, and be securely locked, so axs to rotate therewith.

IOO

IIO

The rear face of the thrust-collar E is smooth or fiat, and interposedbetween said end and the front end of the union-piece or collet D is ahard-metal anti-friction ring, d, such as is shown in the JohnstonandBrowne patent. This ringtakes the wear of the thrust of the spindle andeffectually protects the front end of the union-piece or collet D fromwear. Both the thrust-collar E and the anti-friction -ring d arepreferably of hardened steel fordura bility, and when too much worn theymay be replaced by new ones. The pull-bearing ofthe spindle is formedby. a hard-metal collar, F,

which is fitted to the spindle, and locked thereon from turning by meansof the cone end yof a screw or pin, f, which fits in the. longitudinalgroove b* of thespindle before mentioned. The said pullbearing fisforced firmly up against the rear end of the union-piece or collet D bymeans of a squeeze-nut, G, which is'` screwed upon the threaded end ofthe spindle B, as clearly shown inFig. 1. From this description itwillbe seen that, while the spindle B is capable of freely rotatingaxially in .the union-piece or collet D, still they spindle cannot moveendwise in either direction, while all wear of the thrust and pullcollars may be taken up by the adjustment and the parts readily renewedwhen desired. The unionpiece or collet D at its rear end'iskscrewthreaded for the reception of the internallythreaded front end ofthe casing-section a. Said casing-section, when screwed in place uponthe union-sleeve or collet, is firmly fastened in place by means of aset-screw, g. Projecting upward from the union-piece D is a lug, d',having an opening therethrough extending longitudinally ofthehand-piece, and screw-threaded for the reception of an adj usting-screw,H. The front portion of said unionpiece is smooth, so as to enable therear end of the handle-section c of thecasing to be readily slippedthereon. Said handle-section u of the casing is provided with alongitudinal slot,

a, which permits the rear end of said section to be slipped on the frontend of ythe unionpiece, past the setting device H, and be brought upagainst the end ofthe easing-sections a', so as to form a nice joint.The extent, however, to which the handle-section of the casing isslipped upon the union-piece D" is determined Y'by vthe set-screw H,before mentioned, inasmuch as when the said handle-section is slippedupon the union-piece its inward movement is limited by the shoulderformed at the end of the slot as coming against the front end of saidscrew H. When the handle-section has been slipped upon the union-pieceto its fullest eX- tent as determined by the adjusting device H, it isheld in such position by means of thesetscrew I, having a tapering innerend, which bearsagainst an inclined or wedge surface, d2, formed in theperiphery of the union-piece, as clearly shown in Fig. l. As the saidscrew-is tightened up,.it will `be obvious that the handle-section ofthe casing is wedged backward to its greatest extent as allowed by thesetscrew H, before mentioned. This provision of screws Hand I with theinclined surface d2 of the union-piece is for the purpose'of enablingthe handle-section to be adjusted so as to compensate for any wear ofthe journal or bearing at the front end of the hand-piece, and is asimple and very desirable method of compensating for wear and securingthe proper action of the spindle in the easing.` It will be noticed thatthe screws e, g, and I are constructed with reduced upper or drivingends, and that the openings in which they move terminatein reduceddiameters, whereby-while the screws may be readily turned to performtheir functions, still they cannot be entirely removed, so as to bemislaid'or lost. This is also a'verydesirable feature. v

It will be noticed, also, that the thrust and pull collars E and F arelocked tothe grooved spindle B by means of pins or pointed screws,

whereby they are locked to the spindle and compelled to rotatetherewith, while movable endwise thereon for purposes of adjustment,removal, or replacement. This-is also a desirable feature, because thecircumferential positions of the collars when placed on the spindle mustalways be the same, the collars having the same positionscircumferentially when taken oft' and replaced as before existed.

inasmuch as wear takes place between the coltherein against endwisemovement, but the cone-shoulder on the yshank is also drawn or forced bythe action of a spring firmly in its corresponding seat in the mouth ofthe toolsocket. This avoids endwise movement of the ICO IIO

tool in thesocket and prevents any `wabbling or rattling movement of thetool. Under some circumstances, however, when a pull cut is being madewith a hand-piece like that of Johnston and Brownes, the pull upon thetool wedges the tool-fastening'outward, and the tool pulls out of thesocket. To avoid this difficulty, and to improve the class of tool-locksshown in the Johnston and Browne and Starr patents, we havedevisedy thelocking mechanismwhich'we will now describe.

A longitudinal groove or recess, B', is made in the spindle, and fittedin the front end thereof is a spring-latch, J. The rear end of thislatch is provided with a depending lug, j, sliding in its groove, andthe latch at its front end is provided with a tapering or arrow-shapedhead, j', the lower portion of which forms a hook to engage a shoulderon the tool-shank to lock the tool in the tool-socket, the front end ofthe groove B opening into or communicating with said socket. Thetool-shank is preferably socket and enable it to be readily removed.

provided with two transverse lockiiiggrooves, t' i, and with a reducedend having a drivinglng, i', as usual. Back of the hook end of thelocking-latch is a depending lug, ji, the function of which willpresently be described.

Surrounding the spindle and overlappin g the locking end of the latch Jis an endwisenmovable sleeeve, K, the upper portion of' which is slottedor cut away, as clearly shown in Figs. 1, 2, and 3. The rear end of thissliding sleeve is connected by a link, L, with a ring, M, also fittedupon the spindle so as to move cndwise thereon.

Intcrposed between the frontend of the ring M and a rigid pin orshoulder on the spindle is a coiled spring, N, the tension or stress ofwhich acts to throw and keep the ring M back against the front end ofthe thrust-collar E. This action of the spring consequently, by means ofthe link L, normally retains the slotted sleeve K in the position shownin Fig. 1, with its front end over the front end of thelocking-lateh,whereby said locking-latch cannot rise under anypulling-strain upon the tool.

Vhen it is desired to release the lockinglatch from the tool-shank, soas to permit the tool to be removed, or a new tool to be inserted in itsplace, the ring M is forced forward, carrying with it the link L, whichhas depending lug Z. The first portion of this movement carries thefrontend of the sleeve K forward, and brings its slot above the end ofthe lockinglateh J. As soon as the front end-of the sleeve K has passedfrom above the head of the locking-latch, the lug lof the link L comesagainst the end of the locking-latch and forces it for* ward, causingits inclined or beveled end to ride up the inclined surface b5, formedupon the spindle B, and spring down into a crossnotch, b, in advance ofthe incline b5, above mentioned. The tool-locking latch is then in theposition shownin Fig. 2, and the toolshank is released and may beremoved.

In order to lock the tool-shank in the socket,y the ring M is movedbackward upon the spindle, carrying the sleeve K with it, and as thissleeve comes in contact with the locking end ofthe spring-latch it tripsorforces it over the inclined wedging-shoulder b5, and permits it tospring down into engagement with one of the cross-notches t' of thetool-shank, the head of the locking-latch in its descending movementsdrawing the tool firmly into the toolsocket, with its cone-shoulderfirmly centered in the cone-mouth of said socket of the spindle. As thehead or locking end of the springlatch springs down into engagement withthe tool-shank, to lock itin the socket, the front end of the sleeve Kagain rides over the upper surface of said head, and prevents it fromrising until the said sleeve K is again forced forward. During theunlocking operation the shoulder j2 of the lockingdatch J comes againstan annular shoulder, i, on the tool, formed by reducing the end of thetool-shank, and forces the said tool outward, so as to loosen it in itsThis feature is to overcome the difficulty of withdrawing the tools byreason of their tendency to stick in the socket.

In order to cause the movements of the toolloek which have beendescribed, we preferably employ a gripping pawl or hook, O, actingthrough a slot in the handle-section of the casing, and pivoted at itsforward end to a rocking lever, I), pivoted externally upon the casingat one end, and affording at its other a handle or surface by which torock the lever backward and forward longitudinally of the casing. Theupper surface Aof' the hook or pawl at the point o is rounded orinclined, and the front end of the plate-spring Q, bears upon saidsurface of the latch, so as to keep the rear end of thelatch presseddownward, with a tendency, during the rocking movements of the lever, toenter the opening in the easing and engage the ring M by means of aprojecting point or tooth, o. The extreme rear end of the pawl isprovided with an inclined surface, which, when the lever is in theposition shown in Fig. l, rides up the incline r, so as to carry thepawl out of the recess inthe casing. When the lever I? is rocked in theforward direction, it carries the pawl with it, and this pawl, beingacted upon by the spring before mentioned, is forced down through theslot in the casing, while its tooth o engages the annular shoulder m ofthe ring M, carrying that ring forward, to manipulate the tool-lock andrelease the tool, as before described. y

By reason of the engagement of the end of the locking-latch with thecross-notch b, before described, the tool-locking devices are held intheir unlocked position without frictional contact between the ring Mand the pawl O. This avoidance of friction is a desirable feature,especially when the handpiece is used with motors which it might not bedesirable to stop while changing the bits or tools. W'hen the lever isrocked from front to rear, the tooth o comes in contact with the rearannular shoulder, m', ofthe ring M, and carries the ring backward tolock the tool in the socket, as before descrbed, the pawl at the end ofthe movement of the lever I riding up out of the slot in the casing, asbefore described, thus leaving the spindle free and unretarded in itsrotation.

Any suitable means may be employed to afford a driving-connectionbetween the toolshank and the spindle. In this present i11- stanee weprovide the inner end of the toolsocket witha driving-surface formed bymeans of a tube having its wall at one or more sides slotted for thepassage of the driving-lug i of the tool-shank, as is clearly shown inFigs. l and 2.

Without elaborating the advantages of a handpicce constructed accordingto our invention, and the facilities it affords for accurate adjustment,durability, and efficiency of work, nor of its adaptability for repairsand cleaning of its parts, we state our claim as fol- IOO IIO

lows, first premising that any'and all matter not specically claimedherein is reserved for a future application or applications, and` thatthis reservation of the right to claim any patentable matter disclosedherein, but not now claimed, is not affected or lessened by the makingand cancellation of any claim or claims in the prosecution of thispresent application.

We claim herein-` 1. The combination, with the handle-section of ahand-piece casing, of an external detachable screw-threaded cap fittedto external threads on the nose of said handle-section, substantially asdescribed.

2. A tubular sectional hand-piece casing,

the sections of which are united by a unionpiece carrying an adjustablescrew or device which determines the approach of one section relativelyto Vthe other, substantially as described.'

3. A hand-piece casing the handle-section of which is united to `anothersection by a union-piece the front end of which is fitted `Vto receivesaid handle-section and enable it to be slipped freely endwise thereon,said casing4 ing w'edging device carried by said last-mentioned section,substantially as described.

casing fitted to slide upon the smooth front end of a union-piece orcollet, substantially as described.

6. The combination, with thehand-piece cas-A ing and union-piecethereof, of a spindle fitted to turn in said union-piece, and be lockedfrom endwise movement therein by a thrust-collar on said spindle at thefront of the union-piece, a pull-collar on said spindle at the rear ofsaid union-piece, and alocking device to hold said pull-collar againstthe rear face of said unionpiece, said thrust and pull collars havingprojecting portions fitting a longitudinal groove in the spindle, so asto be incapable of turning on the spindle, while movable endwisethereon, substantially as described.

7. The combination of the longitudinallygrooved spindle, thevpull-collar fitted to move endwise on said spindle, andV provided witha projection tting the groove thereof, and a locking device to retainsaid collar in position.

8. The combination, with the longitudinallygrooved spindle having ashoulder thereon,

of thev thrust-collar fitted to said spindle, and

having a projection tting its groove, whereby the collar may be movedendwise to abut an incline or wedgesuriacetherein, of thethrustcollarfitted to said spindle, and provided with 1 a set-screw the wedge end ofwhich fits the groove of said spindle, and when tightened acts upon theincline thereof, whereby the collar is firmly forced against theshoulder on the spindle and locked securely thereto.

10. The spindleprovided at its forward socketed end with a rigid butdetachable tubular journal, so as to be replaced when worn,substantially as described.

1l. The socketed spindle reduced at its forward end, and having rigidlysoldered. thereto a hardened tubular journal vhaving a tapered or cone'dperiphery to fit a correspondingly-Vv shaped bearing, substantially asdescribed.

12. The internally-threaded and conicallysocketed driving shaftconnection, substantially as described.

18. The endwise-movable tool-locking latch, in combination with thespindle, and the slotted sleeve movable endwise on said spindle over thelocking end of said latch.

14. The combination, substantially as hereinbefore set forth, of thespindle, the endwisemovable tool-locking latch, a ring mounted on saidspindle and fitted to slide thereon to operate said latch, and alink-connection between the latch and ring.

15. The combination of the spindle, the locking-latch, the slottedVsleeve movable on the spindle over the lockingV end of said latch, a

' ring fitted on the spindle to control the movements of Ysaid latch, alink-connection between said ring and said sleeve, whereby the two 5. Ina hand-piece, a'tubular section of theV move together, a projection onsaid link which, at the end of its forward movement, forces the latchforward torelease the tool, and a spring to retract said ring and sleeveto bring the parts of the tool-lock to their locking position,substantially as described. f

16. The combination, substantially as hereinbefore set forth, of aspindle, a spring-operated toolllocking latch carried thereby, and ashoulder or equivalent detent to"` retain the latch in' its unlockedposition, when movedto release the tool, until positively tripped to`move the tool-lock to its locking position.

17. The combination, substantially as hereinbefore set forth, of aspindle fitted to turn in a hand-piece casing, a spring-operated tool.-

- lock carried by saidspindle, a shoulder or equivalent detent to4retain the tool-lock in its unlocked position when moved to release thetool, and a device mounted on the casing .and

IOO

IIO

operating therethrough to manipulate said tool-lock, whereby thetool-lock may be operated, while the spindle is in motion, to release atool, andbe held open as long as desired without frictional conta/ctwith the external operating device. 18. The combination, substantiallyas hereinbefore set forth, with the tool-locking meehanism of adental-engine hand-piece7 of a piv- Oted device carrying an indep endently-pivoted pawl or hook to operate said tool-locking mechanism from theoutside of the casing.

19. The combination, substantially as hereinbefore set forth, of thehand-piece easing, the spindle tted to turn therein, the ring M, fittedto move 011 the spindle, and the lever carrying` a pivoted pawl or hookto move said ring in operating` a tool-locking mechanism.

20. A tool-lock operating apparatus for hand-pieces, consisting of alever, a pawl or hook connected therewith, and a spring acting upon saidpawl, substantially as described.

21. The combination of the hand-piece casing, the spindle fitted to turntherein, the toollocking,` mechanism, the ring fitted to move WM. A.JOHNSTON. A. W. BROWNE. ELI T. STARR. JOHN V. GILBERT. Witnesses:

E. M. WHITE, W M. J. PnY'roN.

